1. Field of the Invention
This invention relates to a retention mechanism for a cassette CPU module, particularly to an improved retention mechanism that can support a snap or a cartridge type CPU module.
2. Description of the Prior Art
Since the PENTIUM II processor made its debut on the stage, INTEL (a leading chip manufacturer has disclosed a serial CPU modules, wherein a CPU in cassette package, a heat sink, and a cooling fan are assembled together one after another on a interface card to form an easy replaceable mounting style. The cassette CPU module may be further classified in two mounting categories, a snap type and a cartridge type that are different in somewhat manner, so that a single common retention mechanism would be preferred to simplify mounting or dismounting of the cassette CPU module.
The interface card of CPU module is plugged into SLOT 1, and inasmuch as the CPU consumes considerable power dissipation, it may be damaged without a heat sink and/or a cooling fan. However, owing to the bulk volume of the cooling devices installed at one side of the interface card, the joint points between the same card and SLOT 1 will suffer an imbalance weight to result in a poor contact or even structural impairment.
Accordingly, a retention mechanism for reinforcement of the construction has been developed for guiding the CPU module when being plugged into the SLOT 1, and in virtue of fixing holes or snap fastening means to hold the cassette CPU module at position firmly for protection of the joint points.
Though the prior retention mechanism can fit both the snap and the cartridge type CPU modules, yet, hands or tools must be employed to pull or unclench one end after the other to detach a snap fastening portion from a fastening recess when trying to release the cassette CPU module in a limited space surrounded by other components. The dismounting job is not only tough but also prone to break the retention mechanism by an improper force.
The prior retention mechanism is fixed to a main board by pressing an insert pin, which will be retained by expending and snap fastening. In the case of dismounting the retention mechanism for some reason, due to a limited area for exerting pulling force, the expanded and snap fastened insert pin cannot be pulled out from the receptacle easily, and owing to lack of stopping point, the pulled out insert pin may fly to anywhere by a quick stroke.
Moreover, another prior retention mechanism uses a fixing cover to cover and snap fasten a snap type CPU module. When a cartridge type CPU module is taken to substitute that of the snap type for one reason or another, the fixing cover cannot be applied to the cartridge type because of different heights and shapes. Thus, the fixing cover has to be dismounted and deposited till next time when a snap type CPU module will be used again.
In view of the above-described defects, this invention is proposed to provide a new structure of retention mechanism for improvement.